Please either format your code or (better!) link to your submission - the forum software has mangled it and it won’t compile! 
Also - what Problem are you trying to solve?
Also also: Are you trying to “Run” without Providing “Custom Input”?
Edit:
int n,a,b,t;int res[n];
You’re declaring an array of size n when n hasn’t been initialised, yet. Your compiler should be warning you about this - if it isn’t, use a better one 